Dear Dr. Cannell,
I’m wondering what change, if any, to the Vitamin D Council’s stance on high-dose Vitamin D3 supplementation will be made based on some of the more recent studies regarding safe limits. Recently, I had a conversation with a local MD with whom I share some patients and she was very concerned about my recommendation for 5000IU/day of D3 to a patient whose levels had recently been tested and found to be at 40ng/mL. The MD’s concerns were due to (possibly mistaken interpretation of) safe limits of trying to “stay less than 50ng/mL” and “definitely less than 75ng/mL.” Pancreatic cancer was the biggest scare quoted by my MD colleague.
I have not been able to find anything in the literature about this level (50ng), but did have my eyes opened a bit after reading the “Overview of the Cohort Consortium Vitamin D Pooling Project of Rare Cancers” with primary author K Helzlsouer.
In my practice, I’m not seeing ANY of my patients’ MDs recommending over 1000 IU/day supplementation these days, and have found it less and less common in the past year to hear of any of my patients getting/taking a Rx for 50,000IU D2 (or D3).
I’m starting to feel like I’m missing something big and I certainly don’t want to be causing more harm than good in recommending high dose Vitamin D3, given my “First, Do No Harm” credo. I first learned about it from Dr. Dave Seaman at a nutritional seminar over 5 years ago and have been taking and recommending it ever since (along with periodic blood level monitoring). I joined the Vitamin D Council a couple years ago and would like to keep better tabs on ongoing recommendations for providers.
Has the frequency of blood testing increased? Should it be monthly while on supplements/Rx instead of every 3 months? Is there a better formula for recommendations based on weight/BMI for absorption? Is there a good way to predict length of supplementation other than blood testing? What are the new “optimal” levels, given that Vitamin D Council used to recommend 50-80ng/mL as the “healthy range,” is 80 pushing the limits of safety for pancreatic cancer?
Sorry for so many questions but I felt like I was caught with my pants down in the above conversation with this doctor!
Ron Himmer, DC, Georgia
Dear Dr. Himmer:
The pancreatic cancer paper you referred to show conflicting data about pancreatic cancer. One study (from a cod liver oil country) shows high vitamin D is associated with pancreatic cancer and another shows it is protective.
A meta-analysis of all papers is simple: the higher your level the lower the risk of pancreatic cancer. I wrote about this before.
It appears the one study you refer to was a statistical artifact.
The frequency of blood testing has increased tremendously in that doctors are ordering more tests. However, as the half-life of 25(OH)D is around six weeks, testing every month makes no sense.
As far as formulas based on weight, they are being worked out as we speak. Robert Heaney wrote the best review on the subject in 2009.
As far as optimal levels, the Endocrine Society recommends that healthy people keep their levels above 30 ng/ml.
Holick MF, Binkley NC, Bischoff-Ferrari HA, Gordon CM, Hanley DA, Heaney RP, Murad MH, Weaver CM; Endocrine Society. Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011 Jul;96(7):1911-30
I agree, but think levels could be and should be a little higher around 50 ng/ml. As far as higher levels, Luxwolda found such levels are common in a naturally living sun exposed group of hunter-gatherers.
I am trained as a zoologist, not just as a physician. I do not believe it is possible that higher vitamin D levels, such as those obtained by equatorial hunter-gatherers, are dangerous. Natural selection does not work that way. That is why I recommend higher levels for anyone with a serious illness. So far, the evidence is quite suggestive that higher levels will help treat disease. There are lots of small randomized controlled trials confirming this. Public health officials are waiting for much larger trials that I believe will confirm that higher vitamin D levels are healthier.
John Cannell, MD